Linux Kernel ext4 CVE-2026-31447

Update to patched kernel versions: 5.10.253+, 5.15.203+, 6.1.168+, 6.6.131+, 6.12.80+, 6.18.21+, 6.19.11+, or mainline 7.0+. Patches available from kernel.org stable trees via git commits referenced in NVD advisories (https://git.kernel.org/stable/c/3822743dc20386d9897e999dbb990befa3a5b3f8 and related commits for each stable branch). Distribution-specific updates should be applied via package managers once vendors release kernel security updates. For systems that cannot immediately patch, implement compensating controls: (1) Restrict filesystem mounting to trusted administrators only by removing mount privileges from unprivileged users via /etc/fstab and polkit policies - note this breaks legitimate user workflows requiring removable media access; (2) Disable auto-mounting of removable media in desktop environments and systemd-udevd rules - reduces USB attack surface but impacts usability; (3) If ext4 bigalloc feature is not required, reformat filesystems without bigalloc to eliminate the vulnerable code path - requires data migration downtime and loses performance benefits; (4) Deploy filesystem integrity monitoring to detect suspicious mount attempts via auditd rules tracking mount syscalls with ext4 type - generates alert noise but provides detection layer. Each mitigation trades functionality or performance for security.